Epidemiology and genetic screening of diarrheagenic Escherichia coli among symptomatic and asymptomatic children.

PURPOSE: Enteropathogens are frequently associated with diarrheal disease. Knowledge of their etiology and epidemiology is essential for the prevention and control of the sickness. This study describes the microbiological and epidemiological features of diarrheal disease in 197 symptomatic and 223 asymptomatic under-five-year-old children from southeastern Brazil, between January 2015 and September 2016. METHODS: Isolation of Escherichia coli, Salmonella, Shigella and Campylobacter was realized by culture. E. coli strains were screened by multiplex PCR, PFGE and O:H serotyping. Antimicrobial susceptibility testing was also performed. RESULTS: Most of the 127 enteropathogens isolated were diarrheagenic E. coli (96.1 %), with predominance of several serotypes of enteropathogenic E. coli (EPEC) and enteroaggregative E. coli (EAEC). Age, sex, rotavirus vaccination, recent use of antibiotics and previous contact with pets, were factors that revealed no significant effects on the probability of infection by the predominant pathogens. Even so, higher incomes could be related to a lesser chance of testing positive for EPEC. Evidence of possible EAEC clonal spread was detected, as well as genetic similarity among strains from both symptomatic and asymptomatic children. Resistance to antimicrobial agents was more pronounced among EAEC than EPEC. CONCLUSION: The occurrence of genetically similar diarrheagenic E. coli in both groups of children, likewise resistant to these agents, underscores the importance of establishing strategies for the prevention of outbreaks, especially among low-income households.

Genotypic and phenotypic analysis of diarrheagenic Escherichia coli strains isolated from Brazilian children living in low socioeconomic level communities.

BACKGROUND: Childhood diarrheal diseases remain highly endemic in developing areas of Brazil. The importance of Escherichia coli among children with diarrhea in these areas was unknown. This study determined the prevalence of different E. coli categories in symptomatic and asymptomatic children from low socioeconomic level rural communities in southeastern Brazil. METHODS: A total of 560 stool samples were collected from 141 children with diarrhea (< 10 years) and 419 apparently healthy controls who resided in 23 communities. E. coli isolates (n = 1943) were subjected to two multiplex PCRs developed for the detection of enteropathogenic E. coli (EPEC), enteroaggregative E. coli (EAEC), diffusely adherent E. coli (DAEC), enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC), and Shiga toxin-producing E. coli (STEC). Strains were also examined for the presence of EPEC, EAEC, and DAEC by assays of adhesion to HEp-2 cells and by hybridization with specific DNA probes. RESULTS: Diarrheagenic E. coli strains were isolated from 253 (45.2%) children, and were associated with diarrhea in children aged < 5 years (p < 0.001). EAEC (20.9%), DAEC (11.6%), EPEC (9.3%) were the most frequent pathotypes, followed by ETEC (2.7%), EIEC (0.5%), and STEC (0.2%). Depending of the assay, EPEC, EAEC, and DAEC (collectively termed enteroadherent E. coli) strains were isolated in 45% to 56% of diarrhea cases, a significantly higher incidence than in controls (P < 0.05). Individually, only DAEC showed significant association with diarrhea (p < 0.05), particularly in children aged 2-5 years. CONCLUSION: This study indicates that enteroadherent E. coli is an important cause of diarrhea in children living in low socioeconomic level communities in southeastern Brazil. Our results reveal that the PCR1 assay is an excellent tool for the identification of EAEC and DAEC.

Características clínicas e epidemiológicas da diarréia aguda por Escherichia Coli enteropatogênica clássica / Clinical and epidemiological characteristics of acute diarrhea by classical enteropathogenic Escherichia coli

Diarréia aguda é tradicionalmente considerada uma síndrome de evoluçao autolimitada na grande maioria dos casos, mas, em algumas cireunstâncias, a influência do agente etiológico, a idade e o estado nutricional do paciente constituem-se em fatores que podem acarretar persistência da diarréia. OBJETIVOS. Neste trabalho, os autores descrevem as características clínicas e epidemiológicas de um grupo de 84 lactentes menores de 2 anos com diarréia aguda provocada por sorogrupos de Escherichia coli enteropatogênica (EPEC). PACIENTES E MÉTODO. Durante período de dois anos, foram estudados 200 lactentes menores de 2 anos de idade, média 8,2 meses, com diarréia aguda de duraçao inferior a cinco días. Grupo controle composto por 40 lactentes sadios, pareados pela idade, foi formado. 0 estado nutricional das crianças foi avaliado e a ocorrência de intolerancia alimentar foi detectada. Os pacientes foram acompanhados clinicamente durante quatro semanas após a alta hospitalar. Amostras de fezes foram colhidas para pesquisa dos principais agentes enteropatogênicos bacterianos, virais e protozoários. RESULTADOS. EPEC foi isolada nas fezes de 84 (42,0 por cento) dos pacientes, dos quais em 55 (27,5 por cento) como agente enteropatogênico único, enquanto que nos 29 (14,5 por cento) restantes associada com outro agente. EPEC foi isolada em 9 (22,5 por cento) crianças pertencentes ao grupo controle (p<0,05). Intolerância alimentar foi a principal complicaçao digestiva e, também, o fator mais importante de perpetuaçao da diarréia. A duraçao média da doença foi de 11,2 dias, variando de 2 a 40 adias. Em 53 (71,6 por cento) lactentes a doença durou menosde 14 dias, enquanto que nos 21 (28 por cento) restantes teve duraçao superior a 14 dias e, em todos estes casos, houve intolerância alimentar. CONCLUSAO. Infecçao intestinal por sorogrupos de EPEC, em particular 0111 e 0119, afeta lactentes preferencialmente menores de 1 ano de idade pertencentes a famílias de baixa renda que sofreram desmame precoce e que necessitam, freqüentemente, internaçao hospitalar devido às grandes perdas fluidas e eletrolíticas fecais.